Because of their many outstanding properties, including self-illumination, short response time, and wide viewing angles, organic light-emitting diode (OLED) displays are widely used in a lot of applications. Nowadays, flexible displays have become a mainstream, next generation display technology.
Currently, in order to realize flexibility and pliability of display apparatus, thin film transistors (TFTs) and display devices are formed on a polyimide (PI) substrate, rather than being formed on a fragile and non-flexible glass substrate. However, owing to its flexible and pliable property, PI cannot serve as a support base plate. Instead, PI is first coated on a glass base plate, and the PI substrate is separated from the glass base plate thereafter using a laser after display devices are finally formed on the substrate, to complete manufacturing of flexible displays. However, in using the laser to remove the glass base plate, a high energy laser would damage electrical properties of TFT devices and consequently decrease product yield. Thus, a bilayer PI structure has been developed, which uses an inorganic barrier layer disposed between the two PI layers to reduce energy of the laser transmitted toward TFT devices. Such a design requires a thick inorganic barrier layer. This adversely reduces the flexibility of the substrate.
Therefore, the inorganic barrier layer of flexible substrates in conventional flexible OLED display panels is thick, which influences the flexibility of flexible OLED display panels, making it difficult for flexible OLED display panels to achieve the desired flexibility.